警告的内容如下：
[code]log4j:WARN No appenders could be found for logger (com.bcodepot.datacrawl.test.AmazonTest).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.[
/code]
